Abstract: The aim of the article is to investigate to what extent Frontex, a European agency, set up in 2004 to reinforce and streamline cooperation between the national border authorities of European countries, participates in the securitisation of migration issues in Europe. To do so, we shall question the origins and the functioning of Frontex comparing two different and complementary perspectives on securitisation, the first one emphasising the concept of ‘speech’ and the second one the concept of ‘practice’. This article suggests that the criminalisation of illegal immigration, the original sin of the European Union in the field of its migration and border management, has Frontex, as a countereff ect, often being accused of operating at the edge of legality. In addition, it argues that the agency suff ered from the inconsistency of the EU in the fi eld of migration and border
issues — what is supranational? what is intergovernmental? — these latter being at the heart of the sovereignty of European countries.

Keywords: European security; Migration; Frontex